The spacecraft was very similar to Venera 4 although it was of a stronger design. When the atmosphere of Venus was approached, a capsule with a mass of 405 kilograms (893 lb) was jettisoned from the main spacecraft. This capsule contained scientific instruments.

During descent towards the surface of Venus, a parachute opened to slow the rate of descent. For 51 minutes on May 17, 1969, while the capsule was suspended from the parachute, data from the Venusian atmosphere were returned. It landed at 5°S23°E﻿ / ﻿5°S 23°E﻿ / -5; 23.

Given the results from Venera 4, the Venera 5 and Venera 6 landers contained new chemical analysis experiments tuned to provide more precise measurements of the atmosphere's components. Knowing the atmosphere was extremely dense, the parachutes were also made smaller so the capsule would reach its full crush depth before running out of power (as Venera-4 had done).

Venera 6 was launched into an Earth parking orbit on January 10, 1969 at 05:51:52 UT and then from a Tyazheliy Sputnik (69-002C) towards Venus. After a mid-course maneuver on March 16 the Venera 6 probe was released on May 17, 1969, 25,000 kilometers (16,000 mi) from the planet.

It entered the nightside atmosphere at 06:05 UT and deployed the parachute. The probe sent back readouts every 45 seconds for 51 minutes and ceased operation due the temperature and pressure effects at roughly 10 to 12 km altitude. The photometer failed to operate, but the atmosphere was sampled at 2 bar and 10 bar pressures.[1]